KR20230164503A - Manufacturing method of cartridge filter - Google Patents

Abstract

A cartridge filter and its manufacturing method are provided. The cartridge filter includes a housing including an inlet and an outlet; and a filtration member installed in the housing and having a plurality of pleats, wherein the filtration member includes a plurality of laminated filtration layers; and at least one mesh layer disposed between the stacked filtration layers. The cartridge filter can maximize flow rate while maintaining a filtration efficiency of at least the same level as that of existing filters in the slurry and ceramic slurry filtration process for the CMP process, thereby improving the customer's production yield and extending the replacement cycle, thereby reducing costs. .

Description

Manufacturing method of cartridge filter {Manufacturing method of cartridge filter}

The present invention relates to a method of manufacturing a cartridge filter. More specifically, a filtration layer using polypropylene meltblown nanofibers without calendaring and a mesh layer within the filtration layer are used to maintain filtration efficiency when filtering slurry and ceramic slurry materials for the CMP (chemical mechanical polishing) process. This relates to a method of manufacturing a cartridge filter that can maximize flow rate.

In general, filters filter impurities contained in liquid or gaseous fluids or various contaminants harmful to the human body, and are used in various fields such as daily life, factories, and workplaces.

As the industry becomes more complex, specialized, and precise, it is inevitable to improve filter functions such as selective filtration technology in all industries, and the development of filters that combine economics and efficiency in the field of microfiltration (MF) is required.

Filtration processes are often applied to filter out contaminants or impurities contained in fluids (liquids or gases) in various manufacturing industries such as semiconductor manufacturing, display manufacturing, and pharmaceutical manufacturing. Typically, nanofiber filters used in the filtration process of materials with relatively high viscosity, such as slurries for CMP processes and ceramic slurries, not only need to secure chemical resistance and filtration efficiency, but also need to maximize flow rate. By maximizing the flow rate, customers' production yield can be improved and the replacement cycle can be extended to reduce costs.

One aspect of the present invention is to provide a method of manufacturing a cartridge filter that can maximize flow rate while maintaining filtration efficiency at an equivalent level or higher compared to existing filters.

One aspect of the present invention is,

Disposing and stacking a plurality of nanofiber filtration layers and at least one interlayer mesh layer between the plurality of nanofiber filtration layers;

Obtaining a filtration member by bonding opposing sides of the laminated product through an ultrasonic fusion process; and

It provides a method of manufacturing a cartridge filter including the step of installing the filtration member in a housing including an inlet and an outlet.

At this time, the nanofiber filtration layer is a meltblown nanofiber containing at least one material selected from polypropylene, polyethylene, polyamide, polyurethane, polyvinylidene fluoride, polyacrylonitrile, and copolymers thereof. It is preferable that it is a non-woven fabric made of.

In addition, it is preferable that the nanofiber filtration layer is a non-woven fabric in an uncalendered state.

At this time, when compared to the calendered filtration layer of the same material, the nanofiber filtration layer in the non-calendered state has a gas permeability (unit L/min) measured by measuring the amount of air passing through the filtration layer at a pressure of 1 psi. It is preferable that it is at least 3 times.

In addition, it is preferable that the thickness ratio occupied by the interlayer mesh layer is 5% to 30% based on the total thickness of the nanofiber filtration layer and the interlayer mesh layer.

In addition, the nanofiber filtration layer preferably has a pore size in the range of 0.1㎛ to 5㎛ and a porosity of 16.7% to 80.0%.

In addition, it is preferable that the number of layers of the nanofiber filtration layer is 2 to 20.

In addition, the plurality of nanofiber filtration layers have different pore sizes, and are preferably stacked in descending order of pore size.

In addition, the interlayer mesh layer is preferably made of a plastic material containing at least one selected from polypropylene, polyethylene, polyamide, polyurethane, polyvinylidene fluoride, polyacrylonitrile, and copolymers thereof.

In addition, it is preferable that the thickness of the interlayer mesh layer is in the range of 0.1 mm to 0.4 mm and the basis weight is in the range of 10 g/m2 to 70 g/m2.

In addition, the interlayer mesh layer is preferably in the form of a mesh having an average pore size in the range of 0.5 mm to 2.5 mm.

In addition, the filtration member further includes an outer mesh layer on the outer surface of the filtration layer and an inner mesh layer on the inner surface,

The external mesh layer has a thickness in the range of 0.1 mm to 0.4 mm, a basis weight in the range of 10 g/m2 to 70 g/m2, and is in the form of a mesh having square-shaped holes,

The internal mesh layer preferably has a thickness in the range of 0.4㎛ to 1㎛, a basis weight in the range of 100g/㎡ to 150g/㎡, and a mesh shape with square-shaped holes.

In addition, after laminating the nanofiber filtration layer and the interlayer mesh layer, it is preferable to further include the step of forming the laminated result into a pleated shape through a pleating process.

In addition, the ultrasonic fusion is preferably performed under conditions where the ultrasonic oscillation time is in the range of 0.5 seconds to 2 seconds and the applied pressure during fusion is in the range of 4 to 6 kg/cm2.

According to one aspect, the manufacturing method of the cartridge filter can maximize the flow rate while maintaining a filtration efficiency of at least the same level as that of existing filters in filtration of slurry and ceramic slurry for the CMP (chemical mechanical polishing) process, thereby improving the production yield of users. It is possible to manufacture a cartridge filter that can reduce costs by extending the replacement cycle.

1 is a schematic diagram showing a cartridge filter according to one embodiment.
Figure 2 is a partial cutaway view of the cartridge filter shown in Figure 1.
Figure 3 is a schematic diagram showing a cartridge filter according to another embodiment.
Figure 4 is a diagram showing a stacking process of a filtration member used in a cartridge filter according to an embodiment.
Figure 5 is a diagram showing a process of forming wrinkles on a filtration member used in a cartridge filter according to one embodiment.
Figure 6 schematically shows an example of a filtration member used in a cartridge filter according to an embodiment.
FIG. 7 shows that in the filtration member shown in FIG. 6, the flow rate is secured without the filtration layer being pressed by the mesh layer.
8 to 11 are diagrams showing various stacking examples of filtration members used in a cartridge filter according to an embodiment.
Figure 12 is a photograph of the inner, middle, and outer mesh layers used in Example 1.
Figure 13 is a scanning electron microscope (SEM) photograph of the nonwoven fabric prepared in Example 1.
Figure 14 is an SEM photograph of the nonwoven fabric prepared in Comparative Example 1.
Figure 15 is an SEM photograph of the nonwoven fabric prepared in Comparative Example 2.
Figure 16 shows the average pore size and gas permeability analysis results of the nonwoven fabrics used in Example 1, Comparative Example 1, and Comparative Example 2.
Figure 17 shows the flow rate versus differential pressure measurement results of the cartridge filters manufactured in Example 1 and Comparative Example 1.
Figure 18 shows the filtration efficiency measurement results of the cartridge filters manufactured in Example 1 and Comparative Example 1.

The present inventive concept described below can be subjected to various transformations and can have various embodiments, and specific embodiments are illustrated in the drawings and explained in detail in the detailed description. However, this is not intended to limit this creative idea to a specific embodiment, and should be understood to include all transformations, equivalents, or substitutes included in the technical scope of this creative idea.

The terms used below are only used to describe specific embodiments and are not intended to limit the creative idea. Singular expressions include plural expressions unless the context clearly dictates otherwise. Hereinafter, terms such as "comprise" or "have" are intended to indicate the presence of features, numbers, steps, operations, components, parts, ingredients, materials, or combinations thereof described in the specification, but are intended to indicate the presence of one or more of the It should be understood that this does not exclude in advance the presence or addition of other features, numbers, steps, operations, components, parts, components, materials, or combinations thereof.

In order to clearly express various layers and areas in the drawing, the thickness is enlarged or reduced. Throughout the specification, similar parts are given the same reference numerals. Throughout the specification, when a part such as a layer, membrane, region, plate, etc. is said to be “on” or “on” another part, this includes not only the case where it is directly on top of the other part, but also the case where there is another part in between. . Throughout the specification, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. Terms are used only to distinguish one component from another.

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and/or regions, these elements, components, regions, layers and/or regions are It will be understood that we should not be limited by these terms.

Additionally, the processes described in the present invention do not necessarily mean that they are applied in order. For example, if the first step and the second step are described, it can be understood that the first step does not necessarily have to be performed before the second step.

In this specification, a cartridge filter refers to a filter that includes a filtration member inside a cage (or housing) that protects the filtration member, and refers to a filter in which the filtration member and cage are installed and replaced together with the filtration member.

Hereinafter, a cartridge filter and a manufacturing method thereof according to an embodiment will be described in detail with reference to the drawings.

A cartridge filter according to one embodiment,

a housing including an inlet and an outlet; and

It includes a filtering member installed in the housing and having a plurality of wrinkles,

The filtration member is,

A plurality of laminated filtration layers; and

It includes at least one interlayer mesh layer disposed between the stacked filtration layers.

Figure 1 is a schematic diagram showing a cartridge filter according to an embodiment, and Figure 2 is a partial cutaway view showing the inside of the cartridge filter.

As shown in Figures 1 and 2, the cartridge filter 100 according to one embodiment includes a housing 110 and a filtration member 120. In Figure 2, the pleated filter member 120, which has a cylindrical outer shape, is shown partially cut away to show the inner core member 130.

In this embodiment, the housing 110 is a case for installing and protecting the filtering member 120, and is a cylindrical cage with an inlet 111 formed on the outer surface. Both ends of the filtering member are provided with an upper end cap 114 having an outlet 112 and a lower end cap 115. In the cartridge filter 100, a core member 130 may be further installed inside the cylindrical filtering member 120 to support the filtering member 120. The material to be filtered before filtration flows into the side through the inlet 111 formed in the housing 110, is filtered through the filtration member 120, and passes through the core member 130 through the outlet of the top end cap 114 ( Exit through 112).

A mounting portion 116 having an outlet 112 may be formed on the upper end cap 114, and two O-rings 117 may be fitted into the mounting portion 116. The number of O-rings 117 may be limited to this. That is not the case. The mounting portion 116 may be provided on the side of the filtration device on which the cartridge filter 100 is mounted. In this case, the outlet 112 is formed directly at the top of the top end cap 114, and the mounting part on the filtration device side is inserted into the outlet 112 on the top end cap 114.

At the periphery of the lower end cap 115, a groove (not shown) may be further provided for setting a jig used when separating the cartridge filter 100 from the filtration device.

According to one embodiment, the housing 110 is in the form of a cage, as shown in FIG. 1, and the outer surface inlet 111 of the cage may be formed on the outer surface. However, according to another embodiment, the housing 110 includes an end cap as shown in FIG. 3. It is formed to include a housing surrounding the entire filtration member, and the filtration target material flows in through the inlet 211 provided at the top of the housing 210 of the cartridge filter 200 and is filtered through the filtration member 120. , passes through a core member (not shown) and exits through the outlet 212 at the top. Here, a mounting part 216' having an inlet 211 may be formed at the top of the housing 210 separately from the mounting part 216 having an outlet 212. One O-ring (217, 217') may be installed in each mounting portion (216, 216'), and the number of O-rings is not limited to this.

The filtering member 120 is installed within the housing 210. The filtering member 120 has a pleated shape with a plurality of wrinkles and a cylindrical outer shape.

In both the embodiment of FIG. 1 and the embodiment of FIG. 3, the filtering member 120 includes, as shown in FIG. 5, a plurality of laminated nanofiber filtration layers 121; and at least one interlayer mesh layer 122 disposed between the stacked filter layers, and wrinkles are formed through a wrinkle process.

The opposing two sides of the wrinkled filtering member 120 can be overlapped and joined to form a cylindrical outer shape. According to one embodiment, opposing two sides of the filtering member 120 may be bonded to each other through an ultrasonic fusion process. The nanofiber filtration layer 121 and the interlayer mesh layer 122 have different material properties, so there is a possibility that complete adhesion may not be achieved and fine leaks may occur due to differences in melting temperature during adhesion, but ultrasonic fusion is possible. The process enables complete bonding between the nanofiber filtration layer 121 and the interlayer mesh layer 122, thereby suppressing the occurrence of fine leaks and maximizing the integrity of the filter.

As illustrated in FIG. 6, the filtration member 120 of the laminated structure is arranged with a plurality of nanofiber filtration layers 121, that is, at least two nanofiber filtration layers 121a and 121b, and these nanofiber filtration layers At least one interlayer mesh layer 122 is disposed therebetween.

Accordingly, the number of nanofiber filtration layers 121 is 2 or more, and the upper limit can be set to an appropriate thickness depending on the filter grade. For example, the number of filtration layers may be 2 to 20, specifically, for example, 2 to 12. Within the above range, the appropriate filtration performance required for the filter can be achieved.

According to one embodiment, the nanofiber filtration layer 121 is a nonwoven fabric made of meltblown nanofibers, and the average diameter of the nanofibers is 400 to 900 nm. At this time, the filtration layer is a single layer or multiple laminated polymer resin nonwoven fabric, and the single nonwoven fabric has an average pore size in the range of 1 to 8㎛ and a thickness of 0.05 to 0.3mm, and the number of layers of the nonwoven fabric is 1 to 15. desirable. If the above range is exceeded, the pore structure of the nanofiber filtration layer becomes finer and the filtration efficiency may be partially improved, but the differential pressure may also tend to increase, and the increase in differential pressure may cause early clogging and frequent replacement. In addition, if the number of layers increases excessively, there is a problem that the thickness of the entire filter media member becomes thick, which may lead to difficulties in side seaming work, such as weakening the ultrasonic fusion strength. The nanofiber filtration layer 121 may include at least one material selected from polypropylene, polyethylene, polyamide, polyurethane, polyvinylidene fluoride, polyacrylonitrile, and copolymers thereof, and is limited thereto. This does not mean that any filtering material commonly used in the relevant technical field can be used without limitation. According to one embodiment, a nonwoven fabric made of polypropylene meltblown nanofibers may be used as the nanofiber filtration layer 121. Polypropylene meltblown nanofibers have good stability in terms of chemical resistance and can be preferably used.

According to one embodiment, the nanofiber filtration layer 121 is preferably made of a non-woven fabric made of meltblown nanofibers in a non-calendered state. Applying calendering may cause phenomena such as reduced porosity and decreased breathability, whereas when non-woven fabric made of non-calendered meltblown nanofibers is applied as a filtration layer, a higher porosity is maintained compared to the calendered case. As a result, it is possible to maximize the flow rate while maintaining a filtration efficiency of at least the same level as that of nanofibers made of other conventional materials.

Compared to a calendered filtration layer of the same material, the non-calendered nanofiber filtration layer 121 has a gas permeability (unit L/min) measured by the amount of air passing through the filtration layer at 1 psi pressure at least 3 times. It may be more than that, and may have gas permeability that is, for example, 4 to 6 times higher. Gas permeability can be measured using methods commonly known in the art. In this way, the non-calendered nanofiber filtration layer 121 has higher gas permeability than the calendered filtration layer of the same material, thereby ensuring high filtration efficiency and maximized flow rate.

The nanofiber filtration layer 121 may have an average pore size in the range of 0.1㎛ to 8㎛, for example, 0.2㎛ to 5㎛, specifically, for example, 0.2㎛ to 0.2㎛. It can have a pore size in the 3㎛ range. Within the above range, a filtration member with excellent particle removal performance can be provided. If it exceeds the above range, the filter filtration efficiency decreases, and if it is below the above range, the differential pressure increases and the lifespan of the filter decreases.

The nanofiber filtration layer 121 may have a porosity ranging from 16.7% to 80.0%, for example, from 33.3% to 54.5%, specifically, for example, from 41.2% to 50.0%. A filtration member capable of securing a high flow rate within the above range can be provided.

According to one embodiment, the plurality of nanofiber filtration layers 121 have different pore sizes and may be stacked in order of decreasing pore size. For example, among the three nanofiber filtration layers in the filtration direction, the first layer in the filtration direction is the 3rd nanofiber filtration layer, the middle is the 2nd nanofiber filtration layer, and the last is the 1st nanofiber filtration layer, In order of pore size, it can be arranged so that the third filtration layer is the largest and the first filtration layer is the smallest.

This layered structure with a pore gradient allows gradual particle removal, which reduces premature clogging of the filter, improves the lifespan of the filter, and allows the construction of a dense filtration layer. In other words, by arranging the filtration layer according to pore size, large particles are removed sequentially, allowing gradual filtration to occur, and at the same time preventing the pores of the next-stage filtration layer, which is made up of finer pore sizes, from being suddenly closed by large particles. This can prevent the life of the filter from being shortened.

The filtration member 120 may further include a support layer on the surface of the plurality of filtration layers 121 with smaller pore sizes. By the support layer, the protective layer at this time may be a MB non-woven fabric with larger pores than the pores of the adjoining filtration layer.

At least one interlayer mesh layer 122 is disposed between the plurality of stacked nanofiber filtration layers 121. The interlayer mesh layer 122 is made of a mesh or net material, which is a different material from the nanofiber filtration layer 121, and is a cartridge filter that has excellent particle removal performance and can secure a high flow rate. can be provided.

As shown in Figure 7, by appropriately mixing and arranging the interlayer mesh layer 122 between the nanofiber filtration layers 121, a separation space can be provided between adjacent nanofiber filtration layers 121, through which CMP When filtering process slurry and ceramic dielectric slurry, the nanofiber filtration layer 121 is not pressed, adjacent nanofiber filtration layers 121 do not stick to each other, and the flow rate is secured through the interlayer mesh layer 122, enabling effective filtration. In this way, the separation space provided by the interlayer mesh layer 122 prevents rapid filter clogging due to compression of the filter member 120 when filtering the slurry for the CMP process and ceramic dielectric slurry, and the resulting decrease in flow rate and shortening of the filter cycle. A Eurozone can be secured for this purpose.

In the filtration member 120, the interlayer mesh layer 122 may be disposed between any two layers of the plurality of nanofiber filtration layers 121, as shown in FIGS. 8 to 10, and one layer may be located in one or more spaces between them. It can be placed more than once. The stacked example of the nanofiber filtration layer 121 and the interlayer mesh layer 122 is not limited to the illustrated example.

As shown in FIG. 11, the filtration member 120 used in the cartridge filter according to one embodiment includes an outer mesh layer 123 on the outer surface of the nanofiber filtration layer 121 and an inner mesh layer on the inner surface ( 124) may be further included. The filtration direction is from the outer mesh layer 123 to the inner mesh layer 124. The outer mesh layer 123 is in the form of a mesh with small-sized openings, and the inner mesh layer 124 is in the form of a mesh with relatively large-sized openings. This shape can increase filtration efficiency. For example, the outer mesh layer 123 may have a thickness in the range of 0.1 mm to 0.4 mm, a basis weight in the range of 10 g/m2 to 70 g/m2, and may be in the form of a mesh having square-shaped opening holes, and the inner mesh may have a mesh shape. The layer may have a thickness ranging from 0.4 μm to 1 μm, a basis weight ranging from 100 g/m 2 to 150 g/m 2 , and a mesh shape having relatively large square-shaped openings. By using the filtration member 120 of this structure, excellent durability and high filtration efficiency can be obtained.

The outer mesh layer 123 protects the nanofiber filtration layer 121 and functions to maintain the filter shape, and the interlayer mesh layer located in the middle forms a passage for fluid to flow as the nanofiber filtration layers are tightly pressed together. This prevents the filter from suddenly clogging as it disappears.

The inner mesh layer 124 does not prevent the nanofiber filtration layers from adhering to each other because the filtration member is in a wrinkled (pleated) shape, but prevents adhesion between mountains in a wrinkled state, so it is more supportive than the outer or interlayer mesh layer. It is thick and has a large opening hole size to ensure strong strength. Accordingly, the opening hole size of the internal mesh layer is larger than that of the external mesh layer or the interlayer mesh layer, and it is desirable to use a different shape of the opening hole and a thicker one.

The outer mesh layer and the interlayer mesh layer preferably have an opening hole size of 1 to 3 mm ² , and the opening hole size of the inner mesh layer is preferably larger, 2 to 5 mm ² .

According to one embodiment, the overall thickness of the filtering member 120 may range from, for example, 30㎜ to 5mm, specifically, for example, from 1mm to 4mm, and more specifically, from 1.2mm to 3mm. there is. If the thickness of the filtration member 120 is too thick, it is filled in the cartridge filter and only has a small area, which may reduce filtration efficiency. Conversely, if the thickness is too thin, the strength deteriorates. Within the above thickness range, a cartridge filter having high filtration efficiency and appropriate strength can be provided.

Meanwhile, the thickness ratio of the interlayer mesh layer to the combined thickness of the nanofiber filtration layer and the interlayer mesh layer may be 5% to 30%. For example, the thickness ratio occupied by the interlayer mesh layer may be 7% to 28%, specifically, for example, 10% to 26%, and more specifically, for example, 12% to 24%. Within the above range, rapid clogging of the filter due to compression of the filtering member 120 can be prevented when filtering slurry for the CMP process and ceramic dielectric slurry, and a flow path can be secured through the mesh layer, thereby maximizing the flow rate.

As a result, the filtration member of this embodiment is a support layer 125, which is formed by first laminating 6 layers of the non-calendered PP nanofiber nonwoven fabric on a meltblown polypropylene nonwoven fabric with a pore size of 50 to 70 ㎛ to form a first nanofiber filtration layer. (121a) is placed thereon, and a polypropylene (PP) plastic interlayer mesh layer (122a) is placed thereon, followed by a second nanofiber filter layer (121b) made of PP nanofiber nonwoven fabric, and a PP plastic interlayer mesh layer (122b). and a third nanofiber filtration layer (121c) made of PP nanofiber nonwoven fabric were sequentially placed to form a three-layer nanofiber filtration layer and a two-layer interlayer mesh layer of PP nanofiber nonwoven fabric.

At this time, in this embodiment, the three-layer nanofiber filtration layer has an average pore size of 0.1㎛ to 8㎛, and the intermediate filtration layer 126 at the top of the third nanofiber filtration layer is a meltblown polypropylene single-layer nonwoven fabric. The average pore size is 10 to 30 ㎛, and the outer filtration layer 127 above the middle filtration layer 126 is a meltblown polypropylene single-layer nonwoven fabric, and the average pore size is 50 to 70 ㎛.

The cartridge filter 100 equipped with the filtration member 120 as described above can be effectively applied to filtration of slurry for the CMP process and ceramic dielectric slurry in production lines such as semiconductors and LCDs that require high-flow, high-performance filters. . The cartridge filter 100 has the advantage of excellent filtration efficiency and foreign matter collection ability and a long lifespan in slurry filtration having a viscosity of 1 cp or more, for example, 1 cp to 200 cp.

A method of manufacturing a cartridge filter according to another embodiment,

Disposing and stacking a plurality of nanofiber filtration layers and at least one interlayer mesh layer between the plurality of nanofiber filtration layers;

Obtaining a pleated-shaped filtration member by performing a pleating process on the laminated result;

Bonding opposing two sides of the filtering member through an ultrasonic fusion process; and

It includes installing the filtering member in a housing including an inlet and an outlet.

The plurality of nanofiber filtration layers may be applied in an uncalendered state. For example, it is preferable that the plurality of nanofiber filtration layers are prepared as a non-calendered nanofiber filtration layer made of meltblown nanofibers. While applying calendaring may cause phenomena such as reduced porosity and decreased breathability, the non-calendered nanofiber filtration layer maintains a higher porosity compared to the calendered case, making it equivalent to nanofibers made of other conventional materials. It is possible to maximize flow rate while maintaining above-level filtration efficiency.

Compared to a calendered filtration layer of the same material, a non-calendered nanofiber filtration layer may have at least 3 times the gas permeability (unit L/min), which is measured as the amount of air passing through the filtration layer at a pressure of 1 psi. , for example, may have 4 to 6 times higher gas permeability.

A plurality of nanofiber filtration layers have different pore sizes and can be stacked in order of decreasing pore size. This layered structure with a pore gradient allows gradual particle removal, which reduces premature clogging of the filter, improves the lifespan of the filter, and allows the construction of a dense filtration layer.

A support layer may be further disposed on the surface of the one with smaller pore sizes among the plurality of filtration layers.

The interlayer mesh layer is composed of a mesh material or net material, which is a different material from the filtration layer of nanofiber material, and can be placed between any two layers among a plurality of filtration layers, and between one or more layers. More than one can be placed in space.

The resulting product laminated in this way is subjected to a pleating process while applying heat of 60 to 160°C to obtain a pleated filter member. Next, the opposing two sides of the filtration member are joined through an ultrasonic fusion process.

If the adhesive strength of the side seaming part connecting the end of the filtration member is weak, or if high pressure is momentarily applied to the cartridge filter, leakage may occur. If a leak occurs in the side seaming part, the material to be filtered passes through as an unfiltered solution, which can cause a very serious and fatal defect to the user.

The cartridge filter according to one embodiment can suppress the occurrence of leaks in the side seaming portion by performing an ultrasonic fusion process to form a side seaming portion with excellent adhesive strength. Important variables in ultrasonic welding are welding time and welding pressure, which are affected by the laminated filter material and arrangement and can therefore change depending on the material and arrangement.

According to one embodiment, during the ultrasonic welding process, the ultrasonic oscillation time, that is, the time to transmit ultrasonic energy to weld opposing sides of the filtration member (also referred to as 'Weld time'), is in the range of 0.5 seconds to 2 seconds, and the welding time is in the range of 0.5 seconds to 2 seconds. The pressing pressure may range from 4 to 6 kg/cm2. Specifically, for example, during the ultrasonic fusion process, the ultrasonic oscillation time may range from 0.7 seconds to 1.5 seconds, and the pressing pressure during fusion may range from 3 to 5.3 kg/cm2. When joining both sides of the filtration member by mutually adjusting the time before ultrasonic oscillation, the time during ultrasonic oscillation, and the pressing pressure during fusion within the above range, a filtration member with strong fusion strength that suppresses leakage at the side seaming portion is used. You can get it.

If the weld time exceeds the above range, the filtering member may melt and become sticky. If the weld time is below the above range, there is a problem in that the bonding strength is weakened due to less adhesion. In addition, if the pressure exceeds the above range, it is strong and there is a risk that it will stick or break due to the pressure, and if it is less than the above range, there is a problem that the bonding strength becomes weak.

At this time, the ultrasonic welding conditions are very important during side seaming because the mesh layer and the plurality of filtration layers composed of a plurality of non-calendered non-woven fabrics must be fused to prevent leakage.

Exemplary embodiments are described in more detail through the following examples and comparative examples. However, the examples and comparative examples are for illustrative purposes only and do not limit the scope of the present invention.

Example 1

(1) Manufacturing non-woven fabric for nanofiber filtration layer

Ultra-fine polypropylene (PP) nanofibers with a diameter of 800 nm are manufactured through a melt blown process in which polypropylene (PP) polymer is melted and extruded and spun through a nozzle with a fine hole, and non-calendered PP nanofibers are produced. Nonwoven fabric (pore size 5㎛, thickness 0.1mm) was manufactured.

(2) Manufacturing the filtration member of the filter

As a support layer, a first nanofiber filtration layer was placed by laminating 6 layers of the non-calendered PP nanofiber nonwoven fabric on a meltblown polypropylene nonwoven fabric with a pore size of 60㎛, and a polypropylene (PP) plastic mesh was placed on top of it. A layer (width x height size 1mm x 1.5mm hole, thickness 0.2mm, basis weight (g/m2)) is placed, followed by a second nanofiber filter layer made of PP nanofiber nonwoven fabric, a PP plastic mesh layer, and a PP nanofiber nonwoven fabric. The third nanofiber filtration layer was sequentially placed to form a three-layer filtration layer and a two-layer interlayer mesh layer of PP nanofiber nonwoven fabric.

At this time, the three-layer nanofiber filtration layer has an average pore size of 1㎛, and a meltblown polypropylene nonwoven fabric is laminated on the top of the third nanofiber filtration layer to form an intermediate filtration layer with an average pore size of 20㎛. A meltblown polypropylene nonwoven fabric was laminated on the top of the layer, and an external filtration layer with an average pore size of 60㎛ was placed.

On the external filtration layer, a PP plastic mesh (rectangular shape, 1x1.5mm size hole, 0.2mm thick) (external mesh layer) identical to the interlayer mesh layer is placed as an external mesh layer, and an internal mesh layer is placed on the lower surface of the support layer. A filtration member was constructed by placing a thicker PP plastic mesh (square shape, diagonal hole size 2mmx1.5mm, thickness 0.7mm).

At this time, the external mesh layer protects the filtration layer and functions to maintain the shape of the filter, and the interlayer mesh layer prevents the filter from suddenly clogging as the passage for fluid flows is lost due to the filtration layers being pressed tightly together. do.

The inner mesh layer does not prevent the filtration layers from adhering to each other because the filtration member has a wrinkled shape, but prevents adhesion between mountains in the pleated state. Therefore, the internal mesh layer must have a stronger supporting force than the outer or interlayer mesh layer. The opening hole size of the mesh layer was larger than that of the external mesh layer or the interlayer mesh layer, and the opening hole shape was configured differently, and a thicker one was used.

The filter member constructed in this way is folded into a wrinkled shape while applying heat at 100°C, and both ends of the filter member are bonded together through ultrasonic fusion under the condition of ultrasonic oscillation for 0.7 seconds and pressurized pressure of 5.3 kg/cm2 to form a cylindrical filter member. was completed.

Figure 12 is a photograph of the inner, interlayer, and outer mesh layers used in Example 1.

(3) Cartridge filter manufacturing

After inserting the filtration member into the filter cage, both ends were melted and bonded with an end cap injection molded product to manufacture a cartridge filter of the type shown in FIG. 1.

Comparative Example 1

A calendered polypropylene fiber nonwoven fabric having the same pore size as the PP nanofibers prepared in Example 1 was manufactured as follows.

A polypropylene microfiber nonwoven fabric (basis weight 25 g) is passed between rotating rolls. At this time, the average pores of the nonwoven fabric are densely compressed by applying constant temperature and pressure to the rotating rolls. This is not calendered in Example 1. A calendered nonwoven fabric with the same pore size as the non-woven PP nanofiber nonwoven fabric was manufactured.

A filtration member and a cartridge filter were manufactured in the same manner as in Example 1, except that the calendered nonwoven fabric was manufactured as above.

Comparative Example 2

A filtration member and a cartridge filter were manufactured by performing the same process as in Example 1, using polypropylene microfiber (hereinafter referred to as 'PP Microfiber') nonwoven fabric (basis weight 25g) instead of nonwoven fabric made of PP nanofibers.

Evaluation Example 1: SEM analysis

Scanning Electron Microscope (SEM) images of the nonwoven fabrics used in Example 1, Comparative Example 1, and Comparative Example 2 are shown in Figures 12 to 14, respectively.

As shown in Figures 12 to 14, the polypropylene nanofiber nonwoven fabric prepared in Example 1 has less fiber compression compared to the nonwoven fabric of Comparative Example 1, which was applied in a non-calendered state and calendered, and the micro fibers of Comparative Example 2 You can see that it is finer than fiber.

Evaluation Example 2: Average pore size and gas permeability analysis

The average pore size of the single nonwoven fabric used in Example 1, Comparative Example 1, and Comparative Example 2 was analyzed simultaneously for pore size and gas permeability through an instrument called a capillary flow porometer. The nonwoven fabric sample to be analyzed was wetted with a wetting solution and all pores were blocked. Afterwards, through air pressure, the wetting solution begins to flow out from the largest pore, generating a fine flow rate. Then, through continuous pressure, the wetting solution sequentially flows out to the smallest pore, increasing the maximum pore size and average pore size depending on the relationship between flow rate and pressure. Size and gas permeability were measured, and the results are shown in Figure 16.

As shown in Figure 16, the polypropylene nanofiber nonwoven fabric prepared in Example 1 has the same average pore size as the calendered nonwoven fabric of Comparative Example 1, but is manufactured with microfibers and a porous structure, so the gas permeability is about 4 times more. You can tell it's excellent. The amount of air passing through the nonwoven fabric at 1 psi pressure was at the level of 7 L/min for the calendered polypropylene nonwoven fabric of Comparative Example 1, while the amount of air passing through the nonwoven fabric of Example 1 was high at 30 L/min. The advantage of using a filter medium with excellent gas permeability is that the differential pressure is lower when manufacturing the filter.

Meanwhile, in the case of the polypropylene microfiber of Comparative Example 2, both the average pore size and gas permeability were large, but in the case of the microfiber, the average pore itself was in the range of 11 to 12㎛, which is more than three times larger than the 3.5㎛ of the nanofiber. You can see that there is. Since the pores are formed large, it is natural that gas permeability is measured to be greater than that of nanofibers, so gas permeability cannot be considered superior to nanofibers. Above all, because the average pores themselves are formed large, one layer of nanofibers forms In order to approach the average pore size, more than 8 layers of microfibers must be stacked, but if stacked in this way, it will be difficult to maintain gas permeability as good as nanofibers. In addition, because the thickness of microfibers is more than twice that of nanofibers, it is not possible to stack them as much as nanofibers based on the same filtration area within the filter. There is also a method of reducing the average pore size by performing calendering to reduce the number of microfiber layers, but this also tends to reduce gas permeability and increase thickness. Therefore, in order to develop a filter that has excellent fine particle removal performance, excellent flow rate, and low differential pressure, it can be said that the existing microfiber filtration layer has limitations in terms of gas permeability and filtration efficiency.

Evaluation Example 3: Filter performance evaluation

In order to compare the performance of the cartridge filters manufactured in Example 1 and Comparative Example 1, the flow rate versus differential pressure was measured by circulating the filter to be tested using water as the test fluid, using a self-made flow rate versus differential pressure measurement facility. Increase from 15L/min to 35L/min. The inlet and outlet pressures of the filter were measured for each flow rate, and the differential pressure was calculated as inlet pressure - outlet pressure, and the results are shown in Table 1 and Figure 17. In addition, using a self-made filtration efficiency evaluation facility, the filtrated solution is mixed with water and test dust (ISO 12103-1, A2 Fine test dust) and passed through the filter to be tested. The water that has passed through the filter is not returned to the undiluted solution tank, but is drained to the drain line. Sampling is performed according to the filtration time (e.g., 2 minutes, 7 minutes after filtration, etc.), and the number of particles in the filtrate is calculated using a particle counter. The removal efficiency was calculated by measuring and comparing it to the number of particles in the stock solution. The results are shown in Table 2 and Figure 18 below.

Flow rate (L/min) Differential pressure (kg/㎠) Example 1 Comparative Example 1 15 0.30 0.86 25 0.50 1.25 35 0.71 1.63

particle size
(㎛) Filtration efficiency (%) Example 1 Comparative Example 1 0.7 99.9075 99.7485 1.0 99.9915 99.9585 2.0 99.9979 99.9863 3.0 99.9989 99.9926 5.0 99.9986 99.9912 7.0 99.9985 99.9943

As shown in Tables 1 and 2 and Figures 17 and 18, the cartridge filter to which polypropylene nanofibers prepared in Example 1 were applied had a lower differential pressure and excellent particle removal efficiency compared to the cartridge filter of Comparative Example 1. You can.

Evaluation example 4: Leak test

In order to confirm the optimal conditions for ultrasonic welding of the filtration member using the polypropylene nanofiber nonwoven fabric prepared in Example 1, ultrasonic welding was performed under the conditions shown in Table 3 below. As a result, when the pressure was increased while reducing the weld time (E case) showed the highest strength.

division Side shimming (ultrasonic fusion) working conditions Leak status Weld (seconds) Pressure (kg/㎠) A 1.5 1.0 Leak occurrence B 1.4 2.0 Leak occurrence C 1.4 4 No leakage D 0.8 5.0 No leakage E 0.7 5.3 No leakage F 2.1 6.1 Leakage, breakage occurs

Although many details are described in detail in the above description, they should be construed as examples of embodiments rather than limiting the scope of the invention. Therefore, the scope of the present invention should not be determined by the described embodiments, but rather by the technical idea stated in the patent claims.

Claims (14)

Disposing and stacking a plurality of nanofiber filtration layers and at least one interlayer mesh layer between the plurality of nanofiber filtration layers;
Obtaining a filtration member by bonding opposing sides of the laminated product through an ultrasonic fusion process; and
installing the filtration member in a housing including an inlet and an outlet;
A method of manufacturing a cartridge filter comprising a. According to paragraph 2,
The nanofiber filtration layer is a nonwoven fabric made of meltblown nanofibers containing at least one material selected from polypropylene, polyethylene, polyamide, polyurethane, polyvinylidene fluoride, polyacrylonitrile, and copolymers thereof. Manufacturing method of in-cartridge filter. According to paragraph 3,
A method of manufacturing a cartridge filter in which the nanofiber filtration layer is a non-woven fabric in an uncalendered state. According to paragraph 3,
The nanofiber filtration layer in the non-calendered state has a gas permeability (unit L/min) measured by the amount of air passing through the filtration layer at a pressure of 1 psi compared to a calendered filtration layer of the same material at least 3 times. Manufacturing method of cartridge filter. According to paragraph 3,
A method of manufacturing a cartridge filter wherein the thickness ratio occupied by the interlayer mesh layer is 5% to 30% based on the total thickness of the nanofiber filtration layer and the interlayer mesh layer. According to paragraph 3,
The nanofiber filtration layer is a method of manufacturing a cartridge filter having a pore size in the range of 0.1㎛ to 5㎛ and a porosity of 16.7% to 80.0%. According to paragraph 3,
A method of manufacturing a cartridge filter in which the number of stacks of the nanofiber filtration layer is 2 to 20. According to paragraph 3,
A method of manufacturing a cartridge filter, wherein the plurality of nanofiber filtration layers have different pore sizes and are stacked in order of decreasing pore size. According to paragraph 3,
The interlayer mesh layer is a method of manufacturing a cartridge filter made of a plastic material including at least one selected from polypropylene, polyethylene, polyamide, polyurethane, polyvinylidene fluoride, polyacrylonitrile, and copolymers thereof. According to paragraph 3,
A method of manufacturing a cartridge filter wherein the thickness of the interlayer mesh layer is in the range of 0.1 mm to 0.4 mm and the basis weight is in the range of 10 g/m2 to 70 g/m2. According to paragraph 3,
The method of manufacturing a cartridge filter in which the interlayer mesh layer is in the form of a mesh having an average pore size in the range of 0.5 mm to 2.5 mm. According to paragraph 3,
The filtration member further includes an outer mesh layer on the outer surface of the filtration layer and an inner mesh layer on the inner surface,
The external mesh layer has a thickness in the range of 0.1 mm to 0.4 mm, a basis weight in the range of 10 g/m2 to 70 g/m2, and is in the form of a mesh having square-shaped holes,
The internal mesh layer has a thickness in the range of 0.4㎛ to 1㎛, a basis weight in the range of 100g/㎡ to 150g/㎡, and a method of manufacturing a cartridge filter in the form of a mesh having square-shaped holes. According to paragraph 3,
A method of manufacturing a cartridge filter further comprising the step of laminating the nanofiber filtration layer and the interlayer mesh layer and then forming the laminated result into a pleated shape through a pleating process. According to paragraph 3,
The method of manufacturing a cartridge filter in which the ultrasonic fusion is performed under conditions where the ultrasonic oscillation time is in the range of 0.5 seconds to 2 seconds and the applied pressure during fusion is in the range of 4 to 6 kg/cm2.

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